so what i decided is to buy a new system....
definitely x79 chipset motherboards...(maybe g1 assassin 2 )
but problem is the current cpus that released from intel so far , is very expensive and intel delayed for releasing other lga2011 until 2012....
i'm planning to buy 3930k.... but very expensive.... waiting for upcoming cpu for LGA 2011.

You'll be paying a pretty penny for any 2011 CPUs, if you want something under 500 go for a 2600k, or 2500k if you're only gaming.

yes only gaming.... (hardcore gaming )
but i want to pick x79 motherboard ( only LGA2011 socket)
which model you suggest me on this socket ?
because i want to buy either gigabyte (g1 assassin 2 / or x79ud7 oc )
so whats your opinion ?
because i want to buy highest end (and also future prooof system ) ! so buying newer platform (x79) is wisely ....
which cpu you suggest me (gamng and under 500$) ?

If you're building now, you can get a Z68 motherboard + either the Core i5 2500k or Core i7 2600k. For gaming only I'd suggest the 2500k as there is no game that can use 8 logical cores effectively and the extra 2MB of cache won't make a difference (the GPU will bottleneck long before then).

__________________"The computer programmer says they should drive the car around the block and see if the tire fixes itself." [src]

If you're building now, you can get a Z68 motherboard + either the Core i5 2500k or Core i7 2600k. For gaming only I'd suggest the 2500k as there is no game that can use 8 logical cores effectively and the extra 2MB of cache won't make a difference (the GPU will bottleneck long before then).

thank u for your advise .
you said about bottleneck . which side of bottleneck you are talking about exactly ? ( remain unused performance... or lack? )
describe more pls.

For gaming the 2500k, 2600k or 2700k are plenty enough you really don't need the newest high end CPU for that. The best bang for the buck right now is probably the 2500k with a decent cooling system it can be easily overclocked. Even at stock speed this CPU is a power house, coupled with a good graphic card there won't be any games that you won't be able to play at max settings.

Don't even bother with X79 if you're only gaming. You won't see any benefit over a 2500K.

You mean x79 is more than gaming ? when there is a newer polatfrom why should i buy older (i mean z68)...
but problem is x79 cpus are very limitted and very expensive.... other lga2011 cpus will not release untill 2012...

if you game only you don't need anything more than 2500k. The LGA 2011 setups are for other stuff than gaming, like working, video editing, or scientific calculations, like Folding at Home, or simulations like Matlab. You could keep the current setup and try a videocard like Radeon 6950/6970 or GTX560/Ti/GTX570 if that does not work then you keep the new videocard and change the rest of the system too. If you take a new mobo with more than one PCIE X16 slots you could also keep the GTS250 as PhysX processor, no matter what card you will add, nVidia or AMD.